This invention relates generally to a prosthetic eye, and, in particular, to a prosthetic eye that provides a direct adjustable coupling between the severed extra-ocular muscles and the prosthetic eye. The prosthetic eye is constructed of a bio-compatible material and further allows for a cosmetically acceptable appearance in the immediate post-operative period.
To date, the prior art reveals many flaws in the construction and insertion of a prosthetic eye. The failures are related but not limited to complications of extrusion of the prosthesis from the orbital tissue as well as potentially fatal orbital infections.
Problems arise due to poor bio-compatibility of the materials used to secure the prosthesis to the tissue surrounding the eye. A variety of materials and devices have been used including prongs, clamps, meshes, and filaments of gold, tantalum, vitallium, and plastic, but are less than completely satisfactory due to the lack of ingrowth between the tissue and that of the foreign material. The poor bio-compatibility of these materials has resulted in loosening of the prosthesis with mechanical erosion of the surrounding tissue causing orbital infection and extrusion of the prosthesis.
In addition, the prior art has obtained poor results due to the lack of an effective method of attaching the conjunctiva to the prosthesis. The implant of a prosthetic eye is a foreign body and therefore its presence increases the risk of orbital infection following surgical implantation. Accordingly, it is necessary to protect the orbital tissues from the ingress of microorganisms by closing the conjunctiva over the implant so that a water-tight seal can be achieved. The prior art has revealed flawed techniques in creating a water-tight seal including purse-string sutures, anchoring the conjunctiva to metallic meshes, and suturing the conjunctiva to itself after passing it through apertures in the prosthesis. However, in all these cases, a gap persisted at the interface of the implant and conjunctiva, resulting in an increased incidence of infection.
Furthermore, the prior art has failed to properly design an implant with the biomechanics to control the eye in a more natural appearing way. In order to achieve the most natural appearing ocular motility, the muscles must be attached to the prosthesis in their anatomic position. Further, to accomplish this goal, the prosthesis must possess a size and shape similar to that of the natural eye. The prior art fails to recreate normal biomechanics necessary to create a more natural appearing prosthetic eye.
Presently, the most accepted technique for the replacement of a diseased natural eye is to remove the eye, suture the remaining extra-ocular muscles over a plastic or glass sphere and then close the conjunctiva and Tenon's membrane over the muscles. After a period of healing, the patient is then measured for a separate cosmetic prosthesis and must further endure several weeks without an eye while the actual construction and art work of the prosthesis is completed. The patient, who has already undergone the trauma of losing an eye, must then be subjected to the additional stress of spending one to two months in a cosmetically unacceptable state.
Further, as discussed above, once inserted, the motility of the cosmetic prosthesis is quite poor due to the absence of any direct connection between the extra-ocular muscles and the prosthesis. Hence, the prosthesis tends to move in a manner that is poorly coordinated with that of the patient's other natural eye giving the patient the appearance of being cross-eyed or wall-eyed. The prior art has failed to provide a prosthetic eye that allows for a cosmetically acceptable appearance in the immediate post-operative period. Additionally, the insertion methods of the prior art have neglected the use of an adjusting prosthetic eye to enable the patient to have a more natural appearing eye.
Accordingly, it is desired to provide a prosthetic eye which is constructed of a bio-compatible material, has an effective method of attaching the conjunctiva to the prosthesis, has the necessary biomechanics to control the prosthetic eye movement and adjust the location of the eye in a natural appearing manner, and a safe and early surgical method of implantation.